We have a situation whereby a supplier is also considered a customer by the company.

They have invoices both for Purchases and Sales. So if we will look at the Sales and Purchase Ledger report. It will show the two invoices coming from two registers and the balance naturally will tell show what is the difference between the two.
DR. CR
Purch Invoice ------------------------- 100K
Sales Invoice ------------------------- 50K _______
Balance------------------------------ 50K

So how do we record this in the sales ledger and the purchase ledger?